Motor vehicle seats commonly have side bolsters on the sides of the seat back, the upright part of the seat. The side bolsters are typically vertically positioned to engage the torso of the seat occupant near the bottom of the rib cage. The side bolsters help maintain the passenger in a fixed position during vehicle maneuvers which might otherwise tend to displace the passenger laterally.
Variable position side bolsters are used to stabilize the seating position of passengers of widely varying proportions by allowing the passenger to adjust the bolsters to an optimal position. However, known variable position side bolsters commonly employ mechanisms which are undesirably complex or expensive. It is desired to provide a simple and inexpensive variable position side bolster for use in motor vehicle seats.